sol2/sol/lua_function.hpp

// The MIT License (MIT)

// Copyright (c) 2013 Danny Y., Rapptz

// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SOL_LUA_FUNC_HPP
#define SOL_LUA_FUNC_HPP

#include "functional.hpp"
#include "stack.hpp"

namespace sol {

template<typename TFx>
struct static_lua_func {
	typedef typename std::remove_pointer<typename std::decay<TFx>::type>::type fx_t;
	typedef detail::function_traits<fx_t> fx_traits;

	template<typename... Args>
	static int typed_call( types<void>, types<Args...> t, fx_t* fx, lua_State* L ) {
		stack::pop_call( L, fx, t );
		return 0;
	}

	template<typename... TRn, typename... Args>
	static int typed_call( types<TRn...>, types<Args...> t, fx_t* fx, lua_State* L ) {
		auto r = stack::pop_call( L, fx, t );
		stack::push( L, std::move( r ) );
		return sizeof...( TRn );
	}

    static int call( lua_State* L ) {
	    void* functiondata = lua_touserdata( L, lua_upvalueindex( 1 ) );
	    //if ( functiondata == nullptr )
	    //    throw sol_error( "call from lua to c++ function has null function pointer data" );
	    fx_t* fx = *static_cast<fx_t*>( functiondata );
	    int r = typed_call( tuple_types<typename fx_traits::return_type>( ), typename fx_traits::args_type( ), fx, L );
	    return r;
    }

    int operator()( lua_State* L ) {
	    return call( L );
    }
};

template<typename T, typename TFx>
struct static_object_lua_func {
	typedef typename std::decay<TFx>::type fx_t;
	typedef detail::function_traits<fx_t> fx_traits;

	template<typename... Args>
	static int typed_call( types<void>, types<Args...>, T& item, fx_t& ifx, lua_State* L ) {
		auto fx = [ &item, &ifx ] ( Args&&... args ) { ( item.*ifx )( std::forward<Args>( args )... ); };
		stack::pop_call( L, fx, types<Args...>( ) );
		return 0;
	}

	template<typename TR, typename... Args>
	static int typed_call( types<TR>, types<Args...>, T& item, fx_t& ifx, lua_State* L ) {
		auto fx = [ &item, &ifx ] ( Args&&... args ) -> TR { return ( item.*ifx )( std::forward<Args>( args )... ); };
		auto r = stack::pop_call( L, fx, types<Args...>( ) );
		stack::push( L, std::move( r ) );
		return 1;
	}

	template<typename... TRn, typename... Args>
	static int typed_call( types<TRn...>, types<Args...>, T& item, fx_t& ifx, lua_State* L ) {
		auto fx = [ &item, &ifx ] ( Args&&... args ) -> std::tuple<TRn...> { return ( item.*ifx )( std::forward<Args>( args )... ); };
		auto r = stack::pop_call( L, fx, types<Args...>( ) );
		stack::push( L, std::move( r ) );
		return sizeof...( TRn );
	}

	static int call( lua_State* L ) {
		const static std::size_t data_t_count = ( sizeof(fx_t)+( sizeof(void*)-1 ) ) / sizeof( void* );
		typedef std::array<void*, data_t_count> data_t;
		data_t fxptrdata;
		int upvalue = 1;
		for ( std::size_t i = 0; i < fxptrdata.size( ); ++i ) {
			fxptrdata[ i ] = lua_touserdata( L, lua_upvalueindex( upvalue++ ) );
		}
		void* objectdata = lua_touserdata( L, lua_upvalueindex( upvalue++ ) );
		//if ( objectdata == nullptr )
		//	throw sol_error( "call from lua to c++ function has null object data" );
		fx_t* fxptr = reinterpret_cast<fx_t*>( static_cast<void*>( fxptrdata.data( ) ) );
		fx_t& mem_ptr = *fxptr;
		T& obj = *static_cast<T*>( objectdata );
		int r = typed_call( tuple_types<typename fx_traits::return_type>( ), typename fx_traits::args_type( ), obj, mem_ptr, L );
		return r;
	}

	int operator()( lua_State* L ) {
		return call( L );
	}
};

struct lua_func {
	static int call( lua_State* L ) {
		void* inheritancedata = lua_touserdata( L, lua_upvalueindex( 1 ) );
		if ( inheritancedata == nullptr )
			throw sol_error( "call from lua to c++ function has null data" );
		lua_func& fx = *static_cast<lua_func*>( inheritancedata );
		int r = fx( L );
		return r;
	}
	
	virtual int operator()(lua_State*) {
        throw sol_error("Failure to call specialized wrapped C++ function from lua");
    }

    virtual ~lua_func() {};
};

template<typename TFx>
struct lambda_lua_func : public lua_func {
    typedef decltype(&TFx::operator()) fx_t;
    typedef detail::function_traits<fx_t> fx_traits;
    TFx fx;

    template<typename... FxArgs>
    lambda_lua_func(FxArgs&&... fxargs): fx(std::forward<FxArgs>(fxargs)...) {}

    virtual int operator()(lua_State* L) override {
        return (*this)(tuple_types<typename fx_traits::return_type>(), typename fx_traits::args_type(), L);
    }

    template<typename... Args>
    int operator()(types<void>, types<Args...> t, lua_State* L) {
        stack::pop_call(L, fx, t);
        return 0;
    }

    template<typename... TRn, typename... Args>
    int operator()(types<TRn...>, types<Args...> t, lua_State* L) {
        auto r = stack::pop_call(L, fx, t);
        stack::push(L, r);
        return sizeof...(TRn);
    }
};

template<typename TFx, typename T = TFx, bool is_member_pointer = std::is_member_function_pointer<TFx>::value>
struct explicit_lua_func : public lua_func {
    typedef typename std::remove_pointer<typename std::decay<TFx>::type>::type fx_t;
    typedef detail::function_traits<fx_t> fx_traits;
    TFx fx;

    template<typename... FxArgs>
    explicit_lua_func(FxArgs&&... fxargs): fx(std::forward<FxArgs>(fxargs)...) {}

    virtual int operator()(lua_State* L) override {
        return (*this)(tuple_types<typename fx_traits::return_type>(), typename fx_traits::args_type(), L);
    }

    template<typename... Args>
    int operator()(types<void>, types<Args...> t, lua_State* L) {
        stack::pop_call(L, fx, t);
        return 0;
    }

    template<typename... TRn, typename... Args>
    int operator()(types<TRn...>, types<Args...> t, lua_State* L) {
        auto r = stack::pop_call(L, fx, t);
        stack::push(L, std::move( r ));
        return sizeof...(TRn);
    }
};

template<typename TFx, typename T>
struct explicit_lua_func<TFx, T, true> : public lua_func {
    typedef typename std::remove_pointer<typename std::decay<TFx>::type>::type fx_t;
    typedef detail::function_traits<fx_t> fx_traits;
    struct lambda {
        T* member;
        TFx invocation;

        template<typename... FxArgs>
        lambda(T* m, FxArgs&&... fxargs): member(m), invocation(std::forward<FxArgs>(fxargs)...) {}

        template<typename... Args>
        typename fx_traits::return_type operator()(Args&&... args) {
           return ((*member).*invocation)(std::forward<Args>(args)...);
        }
    } fx;

    template<typename... FxArgs>
    explicit_lua_func(T* m, FxArgs&&... fxargs): fx(m, std::forward<FxArgs>(fxargs)...) {}

    template<typename... FxArgs>
    explicit_lua_func(T& m, FxArgs&&... fxargs): fx(std::addressof(m), std::forward<FxArgs>(fxargs)...) {}

    virtual int operator()(lua_State* L) override {
        return (*this)(tuple_types<typename fx_traits::return_type>(), typename fx_traits::args_type(), L);
    }

    template<typename... Args>
    int operator()(types<void>, types<Args...> t, lua_State* L) {
        stack::pop_call(L, fx, t);
        return 0;
    }

    template<typename... TRn, typename... Args>
    int operator()(types<TRn...>, types<Args...> t, lua_State* L) {
        auto r = stack::pop_call(L, fx, t);
        stack::push(L, r);
        return sizeof...(TRn);
    }
};

} // sol

#endif // SOL_LUA_FUNC_HPP